The conventional representative process for manufacturing cocoa comprises kibbling the cocoa cake obtained by pressing cacao mass, pulverizing the kibbled product which has once been stored for allowing to cool at the cost of time, cooling the pulverized cocoa powder and then obtaining the finished product by aging.
But the cocoa obtained in accordance with such a conventional process has in most cases a whitish color tone which cannot be generally accepted. This may probably be attributable to the fact that the fat contained in the cocoa particles obtained as the finished product is in the form of coarse crystals.
The expression "cocoa has a good color tone" as used herein means that cocoa has not only deep chocolate color but also gloss.
In order for cocoa to have a good color tone, it is essential that the crystals of the fat contained in the cocoa particles are minute.
It is considered that when the crystals of the fat contained are minute the cocoa particles acquire gloss and as the result assume their original deep chocolate color. On the contrary, however, it is considered that when the crystals of the fat contained are coarse, owing to the diffused reflection of light occurring on the surfaces of the crystals of the fat the cocoa becomes more whitish than original and also more deprived of gloss.
The color tone of cocoa changes as above depending on the state of the crystals of the fat contained therein, but if the color tone of the cocoa product after the manufacture should change during the storage or the like, it is never permissible from the standpoint of the degradation in the commercial value, so that in the manufacture of cocoa it becomes indispensable to obtain the finished product in the state of the crystals of the fat contained being stable.
That is to say, in order to manufacture cocoa which has a good color tone, there should simultaneously be satisfied two conditions that the crystals of the fat contained in the cocoa particles are minute and stable.
The crystals of the fat contained in cocoa are generally apt to be formed in an unstable state. Whether stable crystals are formed or unstable crystals are formed depends on the environmental temperature process. In other words, in order to obtain stable crystals, it is necessary to perform the crystallization at a definite temperature suited for it.
In general it is known that when the crystallization time is prolonged the crystal particles become corase, while when the crystallization time is short, fine crystals are formed. Accordingly, in order to make crystals minute, the fat in the molten state should be rapidly cooled at a temperature as low as possible, but the rapid cooling at a low temperature results in the formation of unstable crystals Also, when cocoa is cooled at the temperature suited for the formation of stable form of crystals in order to cause stabilization of these unstable crystals, the crystallization takes much time and these crystals become coarse.
The term "stabilization" as generally used means a phenomenon that the crystals of the fat transform from their unstable form to stable form. The stabilization in the process according to the present invention, however, is effected to such a degree as is sufficient to maintain a desired product quality of cocoa.
Heretofore, the above described two conditions have been considered to be opposite to each other, so that desirable process which can satisfy these two conditions simultaneously could not be found out.
In the conventional processes, it is difficult to convert all of the molten fat contained in the cocoa into crystals of stable form by means of cooling which is inevitably insufficient. The aging is carried out after the cooling so that the cocoa is stored for a long period of time at a desirable temperature required for formulation of stable crystals in order to avoid the crystals becoming unstable. Such a long time of aging is indispensable to stabilize the crystals. During this aging the crystals are apt to become coarse.
It is considered that as above described, in the conventional processes as the crystallization as well as the stabilization took much time, causing the crystals of the fat contained to become coarse, the cocoa product obtained was nothing but those which were unsatisfactory in the point of the color tone.
Also, in the conventional processes, for their practice there were required many apparatuses and installations, as well as extensive spaces for these apparatuses and installations, and therefore they had many disadvantages from the viewpoints of economy and efficiency.
For instance, in one of the conventional processes, wherein use is made of a double pipe pneumatic cooler, the treating time is extremely shorter than the time required for the crystals of the fat contained to transform into the stable form, so that the crystals of the fat contained in the cocoa powder do not transform into the stable form during this treatment.
Thus, as the aging for the stabilization of the crystals of the fat contained, it is required either that the cooled cocoa powder is once removed into a vessel and allowed to stand for 24 hours in a room at 18.degree.-20.degree. C., or that the powder is once more cooled by means of a cooling apparatus capable of cooling powder.
As above, in general, in the apparatus for manufacturing cocoa not only does the apparatus per se require a large space, but also there are required installations including a constant temperature room for aging, etc.
In addition to the above, there are also required various steps for cocoa powder such as temporary removal into a vessel, transportation for it, storage under cooling, transportation and feeding to the subsequent steps, etc. Furthermore, the conventional apparatuses, which had to be cleaned at frequent intervals, could not be free from a serious defect in the inefficiency arising from the need of downtime for the cleaning.
In view of these problems, the present inventors made extensive investigations, and as the result could find out a process for manufacturing cocoa having a good color tone, wherein even when the formation of crystals of the fat contained in cocoa particles and the stabilization of the thus formed crystals are carried out in one and the same apparatus and in a comparatively short period of time, it is possible to crystallize said fat in the stable form as minute crystals, and yet the treating time as well as the treating apparatus can be saved greatly, and thus this invention could be accomplished.